Kitchen sink plugged. Ran an auger for
quite a long length. Cleanout trap is
totally rusted up and behind toilet so hard
to get good grip on.
ideas?

I'd suggest removing the toilet, a new wax ring only costs a few bucks, this will allow you more leverage and room to work. Use a good penetrating lubricant and let it sit for a couple of hours then try wrenching the pipe use a cheater bar if necessary to gain more leverage.